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-IIITED sTATEs PATENT oEEIcE.

WILLIAM H. LOW, OF ALBANY, NEW YORK.

SAFETY-VALVE.

vSgpecicaton of Letters Patent No. 19,570, dated March 9, 18158.

To all whom it 'may concern.'

Be it known that I, WILLIAM H. Low, of the city and county of Albany and State of New York, have invented certain new and useful Improvements in Auxiliary Safety-Valves for Steam-Boilers; and I hereby declare the following to be a full and exact description thereof, reference being had to the annexed drawings, making a part of this specification, in which- Figure l, is a longitudinal section; and Fig. 2, a horizontal section of the valve and seat through the line m,

The nature of my invention relates to constructing the valve seat of an auxiliary safety valve of a form adapted to the use of a double beat valve whose exposed surfaces are of slightly different areas, and in balancing this difference in area by means of a weight or spring applied directly to the valve, by which means only a comparatively light weight is required, and but a small space is occupied.

The following description will enable others skilled in the art to make and use my invention.

The valve seat, A, has an upper and lower aperture which are closed by the valve, B, formed of the two disks, Z), b', connected together. The. opening, a, a, forms an outlet passage for the steam from the lower aperture to the outer casing. The outer casing, C, which covers and incloses the valve and weight, has an opening through its side, through which the-weight may be adjusted. and which is closed by the cover, D. The perforated plate, E, is placed between the opening, I-I, for the escape pipe and the weight to prevent any tampering therewith. The weight, F, should be made hollow and filled with shot or lead so as to be easily adjusted to the pressure required. The handle, G, has an eye at its upper end which rests upon the top of the casing, C. Its lower end works freely in the hollow spindle, Z2, of the valve, and is provided with a cross pin, g, which when the handle is raised catches in the top of the slotted hole, g, through the hollow spindle and thereby lifts the valve from its seat.

In applying my valve, the seat, A, and casing, C, are bolted together so as to form a steam tight joint, it is then inserted into the boiler and fastened thereto by the lower ianch of the casing, C. The seat, A, being entirely inside of the boiler the steam circulates freely bet-ween the two disks, Z), b, and its pressure tends to keep the lower one down and to force the top one from. its seat, so that it is only the difference between these two forces that has to be compensated for by the weight F. It will readily be seen that however large these disks may be made the difference in their areas need be but slight. Consequently the balance weight required will be but small, thereby overcoming the objections heretofore urged against the use of large safety valves on account of the immense weight or leverage required to obtain high pressures of steam.

rIhe cover, D, may be locked or sealed up after the valve is adjusted, thus placing the valve beyond the reach of any outside communication except by means of the handle, G, which can only be used for raising it, the hollow spindle of the valve raising freely on the handle renders it impossible to apply any extra weight to the valve through its agency.

I am aware that auxiliary safety valves to be weighted to a given pressure and locked up beyond the interference of the engineer or other party, have been used, and I Ado not claim them broadly, but

Vhat I do claim as my invention and desire to secure by Letters Patent is l. The combination of the double beat valve, B, with the seat, A, and weight, F, when arranged in relation to the passages, a, a, and to each other as described and for the purposes set forth.

2. The combination of the double beat valve, B, with the handle, G, casing, C, pin,

g, and slotted hole, g', as and for t-he purposes set forth.

WILLIAM H. LOW.

' Witnesses:

F. P. WINNE,

A. A. VANCE. 

